﻿// Created by amoylel on 12/02/2017.
// Copyright (c) 2017 amoylel All rights reserved.

#ifndef AMO_MD5_HPP__
#define AMO_MD5_HPP__



#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
#endif

#include <string>
#include <cstring>
#include <fstream>
#include <algorithm>


#define F(x, y, z)   ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z)   ((y) ^ ((z) & ((x) ^ (y))))
#define H(x, y, z)   ((x) ^ (y) ^ (z))
#define I(x, y, z)   ((y) ^ ((x) | ~(z)))
#define STEP(f, a, b, c, d, x, t, s) \
		(a) += f((b), (c), (d)) + (x) + (t); \
		(a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s)))); \
		(a) += (b);

#if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
#define SET(n) \
			(*(MD5_u32 *)&ptr[(n) * 4])
#define GET(n) \
			SET(n)
#else
#define SET(n) \
			(ctx->block[(n)] = \
			(MD5_u32)ptr[(n) * 4] | \
			((MD5_u32)ptr[(n) * 4 + 1] << 8) | \
			((MD5_u32)ptr[(n) * 4 + 2] << 16) | \
			((MD5_u32)ptr[(n) * 4 + 3] << 24))
#define GET(n) \
			(ctx->block[(n)])
#endif

namespace amo {



    typedef unsigned int MD5_u32;
    
    typedef struct {
        MD5_u32 lo, hi;
        MD5_u32 a, b, c, d;
        unsigned char buffer[64];
        MD5_u32 block[16];
    } MD5_CTX;
    
    static void MD5_Init(MD5_CTX *ctx);
    static void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size);
    static void MD5_Final(unsigned char *result, MD5_CTX *ctx);
    
    static const void *body(MD5_CTX *ctx, const void *data, unsigned long size) {
        const unsigned char *ptr;
        MD5_u32 a, b, c, d;
        MD5_u32 saved_a, saved_b, saved_c, saved_d;
        
        ptr = (const unsigned char*)data;
        
        a = ctx->a;
        b = ctx->b;
        c = ctx->c;
        d = ctx->d;
        
        do {
            saved_a = a;
            saved_b = b;
            saved_c = c;
            saved_d = d;
            
            STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7)
            STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12)
            STEP(F, c, d, a, b, SET(2), 0x242070db, 17)
            STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22)
            STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7)
            STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12)
            STEP(F, c, d, a, b, SET(6), 0xa8304613, 17)
            STEP(F, b, c, d, a, SET(7), 0xfd469501, 22)
            STEP(F, a, b, c, d, SET(8), 0x698098d8, 7)
            STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12)
            STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17)
            STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22)
            STEP(F, a, b, c, d, SET(12), 0x6b901122, 7)
            STEP(F, d, a, b, c, SET(13), 0xfd987193, 12)
            STEP(F, c, d, a, b, SET(14), 0xa679438e, 17)
            STEP(F, b, c, d, a, SET(15), 0x49b40821, 22)
            STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5)
            STEP(G, d, a, b, c, GET(6), 0xc040b340, 9)
            STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14)
            STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20)
            STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5)
            STEP(G, d, a, b, c, GET(10), 0x02441453, 9)
            STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14)
            STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20)
            STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5)
            STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9)
            STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14)
            STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20)
            STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5)
            STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9)
            STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14)
            STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20)
            STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4)
            STEP(H, d, a, b, c, GET(8), 0x8771f681, 11)
            STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
            STEP(H, b, c, d, a, GET(14), 0xfde5380c, 23)
            STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
            STEP(H, d, a, b, c, GET(4), 0x4bdecfa9, 11)
            STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
            STEP(H, b, c, d, a, GET(10), 0xbebfbc70, 23)
            STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
            STEP(H, d, a, b, c, GET(0), 0xeaa127fa, 11)
            STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
            STEP(H, b, c, d, a, GET(6), 0x04881d05, 23)
            STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
            STEP(H, d, a, b, c, GET(12), 0xe6db99e5, 11)
            STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
            STEP(H, b, c, d, a, GET(2), 0xc4ac5665, 23)
            STEP(I, a, b, c, d, GET(0), 0xf4292244, 6)
            STEP(I, d, a, b, c, GET(7), 0x432aff97, 10)
            STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15)
            STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21)
            STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6)
            STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10)
            STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15)
            STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21)
            STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6)
            STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10)
            STEP(I, c, d, a, b, GET(6), 0xa3014314, 15)
            STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21)
            STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6)
            STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10)
            STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15)
            STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21)
            
            a += saved_a;
            b += saved_b;
            c += saved_c;
            d += saved_d;
            
            ptr += 64;
        } while (size -= 64);
        
        ctx->a = a;
        ctx->b = b;
        ctx->c = c;
        ctx->d = d;
        
        return ptr;
    }
    
    static void MD5_Init(MD5_CTX *ctx) {
        ctx->a = 0x67452301;
        ctx->b = 0xefcdab89;
        ctx->c = 0x98badcfe;
        ctx->d = 0x10325476;
        
        ctx->lo = 0;
        ctx->hi = 0;
    }
    
    static void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size) {
        MD5_u32 saved_lo;
        unsigned long used, free;
        
        saved_lo = ctx->lo;
        
        if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo) {
            ctx->hi++;
        }
        
        ctx->hi += size >> 29;
        used = saved_lo & 0x3f;
        
        if (used) {
            free = 64 - used;
            
            if (size < free) {
                memcpy(&ctx->buffer[used], data, size);
                return;
            }
            
            memcpy(&ctx->buffer[used], data, free);
            data = (unsigned char *)data + free;
            size -= free;
            body(ctx, ctx->buffer, 64);
        }
        
        if (size >= 64) {
            data = body(ctx, data, size & ~(unsigned long)0x3f);
            size &= 0x3f;
        }
        
        memcpy(ctx->buffer, data, size);
    }
    
    static void MD5_Final(unsigned char *result, MD5_CTX *ctx) {
        unsigned long used, free;
        used = ctx->lo & 0x3f;
        ctx->buffer[used++] = 0x80;
        free = 64 - used;
        
        if (free < 8) {
            memset(&ctx->buffer[used], 0, free);
            body(ctx, ctx->buffer, 64);
            used = 0;
            free = 64;
        }
        
        memset(&ctx->buffer[used], 0, free - 8);
        
        ctx->lo <<= 3;
        ctx->buffer[56] = ctx->lo;
        ctx->buffer[57] = ctx->lo >> 8;
        ctx->buffer[58] = ctx->lo >> 16;
        ctx->buffer[59] = ctx->lo >> 24;
        ctx->buffer[60] = ctx->hi;
        ctx->buffer[61] = ctx->hi >> 8;
        ctx->buffer[62] = ctx->hi >> 16;
        ctx->buffer[63] = ctx->hi >> 24;
        body(ctx, ctx->buffer, 64);
        result[0] = ctx->a;
        result[1] = ctx->a >> 8;
        result[2] = ctx->a >> 16;
        result[3] = ctx->a >> 24;
        result[4] = ctx->b;
        result[5] = ctx->b >> 8;
        result[6] = ctx->b >> 16;
        result[7] = ctx->b >> 24;
        result[8] = ctx->c;
        result[9] = ctx->c >> 8;
        result[10] = ctx->c >> 16;
        result[11] = ctx->c >> 24;
        result[12] = ctx->d;
        result[13] = ctx->d >> 8;
        result[14] = ctx->d >> 16;
        result[15] = ctx->d >> 24;
        memset(ctx, 0, sizeof(*ctx));
    }
    
    
    
    class md5 {
    public:
        /* Return Calculated raw result(always little-endian), the size is always 16 */
        static void md5bin(const void* dat, size_t len, unsigned char out[16]) {
            MD5_CTX c;
            MD5_Init(&c);
            MD5_Update(&c, dat, len);
            MD5_Final(out, &c);
        }
        
        static char hb2hex(unsigned char hb) {
            hb = hb & 0xF;
            return hb < 10 ? '0' + hb : hb - 10 + 'a';
        }
        
        static std::string md5_file(std::FILE* file) {
        
            MD5_CTX c;
            MD5_Init(&c);
            
            char buff[BUFSIZ];
            unsigned char out[16];
            size_t len = 0;
            
            while ((len = std::fread(buff, sizeof(char), BUFSIZ, file)) > 0) {
                MD5_Update(&c, buff, len);
            }
            
            MD5_Final(out, &c);
            
            std::string res;
            
            for (size_t i = 0; i < 16; ++i) {
                res.push_back(hb2hex(out[i] >> 4));
                res.push_back(hb2hex(out[i]));
            }
            
            return res;
        }
        static std::string invalid_md5() {
            return "00000000000000000000000000000000";
        }
        static std::string md5_file(const char* filename) {
            std::FILE* file = std::fopen(filename, "rb");
            
            if (file == NULL) {
                return invalid_md5();
            }
            
            std::string res = md5_file(file);
            std::fclose(file);
            return res;
        }
        
        static std::string encrypt(const void* dat, size_t len) {
            std::string res;
            unsigned char out[16];
            md5bin(dat, len, out);
            
            for (size_t i = 0; i < 16; ++i) {
                res.push_back(hb2hex(out[i] >> 4));
                res.push_back(hb2hex(out[i]));
            }
            
            return res;
        }
        
        static std::string  encrypt(const std::string&  dat, bool upperCase = true) {
            std::string val = encrypt(dat.c_str(), dat.length());
            
            if (upperCase) {
                std::transform(val.begin(), val.end(), val.begin(), ::toupper);
            }
            
            return val;
        }
        
        static std::string encode(const std::string& data, bool upperCase = true) {
            std::string val = encrypt(data);
            
            if (upperCase) {
                std::transform(val.begin(), val.end(), val.begin(), ::toupper);
            }
            
            return val;
        }
        
        static std::string encode(std::FILE* file, bool upperCase = true) {
            std::string val = md5_file(file);
            
            if (upperCase) {
                std::transform(val.begin(), val.end(), val.begin(), ::toupper);
            }
            
            return val;
        }
        
        static std::string encode_file(const std::string& file_name,
                                       bool upperCase = true) {
            std::string val = md5_file(file_name.c_str());
            
            if (upperCase) {
                std::transform(val.begin(), val.end(), val.begin(), ::toupper);
            }
            
            return val;
        }
        
        /* Generate shorter md5sum by something like base62 instead of base16 or base10. 0~61 are represented by 0-9a-zA-Z */
        static std::string md5sum6(const void* dat, size_t len) {
            static const char* tbl =
                "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
            std::string res;
            unsigned char out[16];
            md5bin(dat, len, out);
            
            for (size_t i = 0; i < 6; ++i) {
                res.push_back(tbl[out[i] % 62]);
            }
            
            return res;
        }
        
        static std::string  md5sum6(const std::string&  dat) {
            return md5sum6(dat.c_str(), dat.length());
        }
    };
    
    
}



#endif // AMO_MD5_HPP__